The acquirement of robust variogram in reservoir modeling

According to detailed study on the vertical characters of the petroleum well logs and the three main geological factors such as outliers, mixed distribution and drift which influenced the acquirement of the robust variogram of reservoir petrophysical parameters, the paper used removing outliers, clipping pair data which had extra high difference, data normal transform, and so on to eliminate the effect of outliers, and used facies particular description or tail-cut to reduce mixed distribution influence. The paper also caculated the variogram of the residuals obtained by removing the trend to reduce the drift effect, and at last put foward the working flow of the robust variogram acquirement of petroleum reservoir parameters.